Police officers place flowers outside a nightclub in Santa Maria, Brazil, where 233 died in a fire.

Photo: Antonio Scorza, AFP/Getty Images

Police officers place flowers outside a nightclub in Santa Maria,...

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A relative of one of the nightclub fire victims grieves at the municipal cemetery in Santa Maria.

Photo: Antonio Scorza, AFP/Getty Images

A relative of one of the nightclub fire victims grieves at the...

Image 3 of 3

Policemen stand guard outside the Kiss nightclub where a blaze on the eve killed more than 230 people, on January 28, 2013, in Santa Maria, southern Brazil. Brazilian police arrested four suspects --two of the Kiss club's owners, along with a pair of musicians who starred in the ill-fated pyrotechnic show, in the wake of the nightclub fire that forced sports officials to defend preparations for the World Cup and Olympics.. AFP PHOTO ANTONIO SCORZAANTONIO SCORZA/AFP/Getty Images

Four people have been arrested in connection with a deadly fire that swept through a Santa Maria nightclub killing 233 revelers early Sunday, as Brazil mourned the victims and families identified the dead.

Those arrested included an owner of the nightclub and two members of the band performing at the time of the fire, police confirmed.

Most of the victims were between 18 and 23 years old. Many minors were also killed, and at least 217 people were injured.

About 121 people remained hospitalized Monday - 80 of them listed in serious condition, said Health Minister Alexandre Padilha.

"These are patients who are in intensive care, with mechanical help to breathe," Padilha said.

Brazilian authorities have contacted skin banks in neighboring countries, including Argentina, Uruguay and Peru, in case they need assistance to perform grafts for those suffering severe burns.

The victims' families queued outside a sports center, which had become a makeshift morgue, to identify their loved ones from the bodies that were laid out in a row with plastic sheets covering all but their faces.

Up to 80 bodies were to be buried Monday in Santa Maria.

The nightclub had a capacity for 2,000 people. Preliminary information indicated that the fire was sparked by a pyrotechnics display during a concert attended largely by students from a nearby university, one of Brazil's largest.

Sparks hit the soundproof foam on the ceiling and caught fire, according to broadcaster Globo. Many people were unable to reach the emergency exits in the ensuing panic.

Firefighters broke holes in the walls in a futile effort to rescue survivors. When they finally managed to enter, they saw a pile of bodies.

President Dilma Rousseff abruptly cut short her participation in the European Union-Latin American summit in Santiago, Chile, to travel Sunday to Rio Grande do Sul, which is also her home state.

"I wanted to tell the people of our country and of Santa Maria that we are all together at this moment of sadness," she said with tears in her eyes. "And we will overcome this, though the sadness will remain."